What is the best way to auto start multiple existing dependent containers?

I have a wordpress container which depends on another mysql container. Basically I want to automatically start them at startup time. As there is dependency between them, I am wondering how could I ensure this dependency.

I've taken a look at docker-compose, but it seems that docker-compose can only manipulate images instead of containers. As I don't want to mount volumns from container to my host, I don't want to create new container every time.

I've also taken a look at manually create two services using systemd. But it is difficult to decide if mysql is launched(Although the container has been launched, its service still needs more time.).

So what is the recommended way to launch dependent containers at startup time?

Solution

You can use the depends_on param to manage the dependencies Here is the compose file for your usecase

version: '3.3'

services:
   db:
     image: mysql:5.7
     volumes:
       - db_data:/var/lib/mysql
     restart: always
     environment:
       MYSQL_ROOT_PASSWORD: somewordpress
       MYSQL_DATABASE: wordpress
       MYSQL_USER: wordpress
       MYSQL_PASSWORD: wordpress

   wordpress:
     depends_on:
       - db
     image: wordpress:latest
     ports:
       - "8000:80"
     restart: always
     environment:
       WORDPRESS_DB_HOST: db:3306
       WORDPRESS_DB_USER: wordpress
       WORDPRESS_DB_PASSWORD: wordpress
volumes:
    db_data: {}

More Info: https://docs.docker.com/compose/wordpress/